Excitation of Pc5 pulsations of the geomagnetic field and riometric absorption

We consider in detail the intense Pc5 pulsations of the magnetic field, riometric absorption, and electron fluxes occurred on the recovery phase of the strong magnetic storm on November 21, 2003. The global structure of these disturbances is studied using the world network of magnetometers and riometers supplemented by the data of particle detectors onboard the LANL geosynchronous satellites. The local spatial structure is investigated according to data of the regional network of Finnish vertical riometers and of stations of the IMAGE magnetic network. Though a certain similarity is observed in the frequency composition and time evolution of the variations of magnetic field and riometric absorption, the local spatial structure of these oscillations turns out to be different. It is suggested that these variations can be manifestations of oscillatory properties of two weakly connected systems: the magnetospheric MHD waveguide/resonator and the system cyclotron noise + electrons. The recorded Pc5 oscillations are, presumably, a result of excitation of the magnetospheric waveguide on the morning and evening flanks of the magnetosphere. At high velocities of the solar wind this waveguide can appear in a metastable state. Not only jumps in the solar wind density, but injection of electrons into the magnetosphere as well, can serve as a trigger for the waveguide excitation.     

Observations of interplanetary shocks: Recent progress

Interplanetary shock observations since the prior Solar Terrestrial Physics Symposium in 1978 are reviewed. Since the interval coincides with the recent solar maximum, emphasis is placed on shocks associated with transient solar phenomena, including coronal transients and eruptive prominences as well as flares. A good correlation between shocks and Storm Sudden Commencements has persisted into the recent maximum. Shocks have been identified that are associated with disappearing filaments and coronal transients rather than with flares. Significant progress has been made in the indirect observation of shocks near the Sun as a result of radio wave measurements in interplanetary space and measurement of the scintillation and spectral broadening of spacecraft radio transmissions. Preliminary results regarding the thickness of interplanetary shocks have appeared. Several quasi-parallel shocks propagating more nearly along, rather than across, the magnetic field have been identified. The plasma drivers accompanying interplanetary shocks have received increased attention and distinctive features have been found in electron, ion and magnetic field data.     

A technique of shaping the barrel-type parts

In this paper, a new technique for shaping the thin-walled barrel-type parts is presented.     

Approximate analytical solutions of stability problems for skew plates under combined loading

The known analytical solutions of the linearized stability problems for rectangular hinged plates under the combined loading are generalized to the similar problems for skew plates, the deformation mechanics of which is described by the equations of the classical theory formed in the oblique Cartesian coordinates.     

Experimental study of radial temperature gradient-reducing devices in GTE rotor disks

In this paper, we examine experimentally some devices the principle of action of which is based on using the dynamic pressure of air extracted to engine cooling and which are meant for reducing the radial temperature gradient in GTE rotor disks. We established that the devices equipped with the ejector channels make it possible to accelerate the process of the disk hub heating by hot air suction from the cavity periphery towards the rotor axis of rotation. Using the data of visualization studies, we show the possibility for efficient operation of ejector devices in the conditions of real GTE rotor circumferential velocities.     

Optimization of electrode system for the aircraft time-of-flight ion-marking airspeed and angle of attack sensor

A technique of optimizing the electrode system of the differential recorder for the aircraft time-of-flight ion-marking airspeed and aircraft angle of attack sensor by the criterion of ion-marking recording error variance minimum is considered. The technique is based on analyzing the function of spatial distribution for the ion-marking and recorder electrode interaction field potential and determining a point for which this function reaches the maximum slope. The relations making it possible to synthesize the sensor electrode system by the complex criterion as a ratio of error variance to transformation channel response are obtained.     

A lower bound estimate of the critical load for helicopter main rotor composite blade according to the limit equilibrium theory. The basic steps of an algorithm

The basic steps of an algorithm are given for calculating the parameters of the limiting state of a helicopter main rotor blade. To estimate the static strength, a technique of elastic constants variation is used; it is based on the limit equilibrium theory and enables us to obtain the upper and lower bounds for the critical load simultaneously. An iterative technique is proposed to determine the lower bound of the allowable load on the root section of the composite blade depending on the azimuthal angle of its turn in the helicopter hovering mode.     

Analysis of flow past oscillating cascades by the implicit method to evaluate the cascade aeroelastic stability in viscous flow

A technique of analyzing the flutter initiation in flat plate compressor cascades was developed. The viscous and inviscid flow study was carried out using the COBRA solver based on the modified implicit Godunov method and unsteady implicit method updated for using. The flutter conditions were revealed and the effect of taking into account viscosity, angles of attack and time steps was investigated.     

Determination of the influence of a clearance between the case and blade ends of the semi-open impeller on the centrifugal compressor stage characteristics

The influence of the clearance between the case and blade ends of the semi-open impeller on the centrifugal stage characteristics is considered using the experimental data and numerical calculation results.     

Influence of geometry and operating conditions of a centrifugal compressor stage on the radial gas force

The influence of geometry and operating conditions of the centrifugal compressor stage on the radial gas force is determined on the basis of the theoretical method and calculation program using experimental boundary conditions.